More than 80 charities have joined forces this week to launch the first-ever campaign aimed at encouraging more people to donate money in their wills. Remember A Charity is primarily targeted at the over-50s, who represent the bulk of charitable donors.

It aims to raise an extra £180million over the next two years for both charities and the entire voluntary sector. Backed by the Institute of Fundraising and the Giving Campaign, the consortium is the biggest combined charity initiative of its kind in the UK. It includes well-known names such as Barnardo's, NSPCC, Macmillan, WWF, Oxfam, Red Cross and Mencap alongside smaller local charities.

While seven out of 10 people donate money during their lifetime, only 4% leave any in their will.

Research by NOP World showed that a key reason for this was confusion over the legal terminology involved in drawing up a will, and a general lack of awareness of the tax breaks on charitable donations. This is why the charities have enlisted the help of trade bodies representing solicitors, financial advisers and others involved in drawing up wills, to help raise awareness and dispel the myths surrounding charitable legacies.

The research also showed that many people were worried that they were not well off enough to make charitable donations, seeing it as the preserve of the well-heeled. Others expressed concern over how the money would be spent.

Those that do leave money to charities usually do so to organisations which they have been involved with in one way or another, during their life. Graham Wright from Southport, Merseyside has donated money to Macmillan cancer relief after his friend, Alan, suffered a brain tumour. "During his illness, he received support and care from a Macmillan nurse. Adding Macmillan to my will seemed a perfect way to say 'thank you' on Alan's behalf, and to make sure that the charity would be able to support people in the future."

And Charles Roland from Christchurch, Dorset has bequeathed money to Barnardo's.

He and his late wife used to work as house parents at a home for boys, many of whom still keep in contact and visit with their children and grandchildren.

Now in his 80s, with no dependants, Charles says: "I truly believe that the work Barnardo's does is of great value to young people, and I want to contribute to the ongoing work."

So, how do you donate in your will? The simplest way is to make a "pecuniary" bequest - that's legalese for setting aside a specific amount, or a particular item, for a charity or charities of your choice. The downside is that as the value of your assets change, you could end up having to constantly change your will with all the extra legal costs that involves.

The alternative is to either leave a percentage of your estate or to make a "residuary" bequest - basically you leave what's left after providing for anyone else, and after any debts and expenses have been paid.

Bequests to charities are exempt from tax which not only benefits the charity but, because they're not included in the value of your estate, can reduce any inheritance tax.

Donations to charities can be made after your death if the beneficiaries of your will use a deed of variation.

It could, for example, be used to donate enough to charity to bring the total value of the estate below the inheritance tax threshold which is currently £250,000, so no IHT would need to be paid.

Despite the legal jargon, making the bequests is fairly simple. But, if you're unsure and think you're likely to change your mind as time goes by as to which charities should benefit, then it is worth considering a legacy account with the Charities Aid Foundation.

The CAF will keep and, if necessary, amend the list of charities you want to leave money to without imposing any charges. It will distribute the money according to your wishes.

As well as giving you flexibility without incurring extra costs, the CAF can also suggest the relevant clauses that should be included in your will, and confirm whether any organisation you wish to bequeath money to is recognised by the Inland Revenue as a registered charity.

If you have relatively large amounts of money that you want to donate, then it may be worth considering a charitable trust through your will.

This is a more complex route and you will need professional advice. An easier way is to set up a trust through the CAF. It will manage it and distribute the proceeds according to your wishes.

But, well-heeled or not, the key theme of the Remember a Charity Campaign is that: "Everyone can leave the world a better place."

Remember a Charity: rememberacharity or tel 0808-180-2080. It provides broad guidance on how to include a donation in your will, details of participating charities, an inheritance tax calculator and links to help you find a solicitor.